ST. PAUL, Minn. (AP) — The group that pushed Minnesota lawmakers to legalize gay marriage disclosed Wednesday it invested more than $2 million in the successful lobbying effort.

Minnesotans United for All Families leader Richard Carlbom provided the figure to The Associated Press ahead of a mid-June deadline to report lobbying during the just-completed legislative session. About $400,000 to $500,000 was spent on TV ads, he said.

READ MORE: Former Minneapolis Superintendent Bernadeia Johnson Fighting Stage 5 Kidney Disease

Minnesotans United likely will rank at or near the top of 2013 legislative lobbying, if historical spending is any guide. The Minnesota Chamber of Commerce and Xcel Energy are the only entities to recently surpass the $2 million mark in a single year, and some of that includes lobbying state utilities regulators.

The Minnesotans United money fueled a personal lobbying effort, phone banks and television commercials. The group used 14 lobbyists.

In contrast, the main opposition group, Minnesotans for Marriage, had three registered lobbyists.

Gay marriage advocates went from narrowly defeating a constitutional amendment to ban same-sex marriage last fall to winning the new law in mid-May.

READ MORE: Ex-Soldier's Company Works To Provide Security, Peace Of Mind For Churches

“In order to be successful in the legislative effort, we couldn’t let it feel like there was any letup at all,” Carlbom said of the heavy spending.

The turnabout was sudden, but not entirely surprising given the Democratic takeover of both legislative chambers.

With majorities sympathetic to their cause, supporters of gay marriage saw the legislation pass with room to spare. In the House, it passed 75-59 with four Republicans joining all but two Democrats. Days later, the Senate approved the bill 37-30 with one Republican in favor and three Democrats joining the opposing side.

Gov. Mark Dayton signed the bill in front of a crowd of thousands. Minnesota was the first Midwestern state to enact gay marriage through legislative vote and the 12th state overall to allow it. Couples can begin to wed on Aug. 1.

Minnesota United has now shifted gears. In has set up a political action fund that group leaders say will be used to help legislators who voted for gay marriage in their next campaigns.

MORE NEWS: Police: Boy's Body Found In Trunk Of Car In Mound, 2 Arrested

(© Copyright 2013 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)